The five scientific projects proposed in this programs are highly interconnected since they involve the collection of several different types of data from common subject groups. Furthermore patients in these projects will be followed over several years. Consequently many of these specific aims of the program can only be achieved if there is an efficient system of centralized data management. The specific aims of this core are: 1) To maintain computerized data files for information derived from the individual projects and cores, 2) To conduct ongoing quality control checks of the database, 3) To provide data summaries to investigators upon request, 4) To provide statistical consultation to investigators, 5) To perform statistical analyses as needed. All projects will use this core.